From The Collaborative International Dictionary of English v.0.48 :
Hybridize \Hy"brid*i`ze\, v. t. [imp. & p. p. Hybridized; p.
pr. & vb. n. Hybridizing.]
To render hybrid; to produce by mixture of stocks.
[1913 Webster]
From WordNet (r) 3.0 (2006) :
hybridizing
n 1: (genetics) the act of mixing different species or varieties
of animals or plants and thus to produce hybrids [syn:
hybridization, hybridisation, crossbreeding,
crossing, cross, interbreeding, hybridizing]